There are many ways the two wastelands can interact with one another. There are so many ways I can't even list them but I can throw out a few as an example. Let your imagination and logics run wild. :D For example, after Raven's Rock, and you've been to Jacob's Town, you could tell Farkus about Jacob's Town, a town full of smart Super Mutants, so he can visit and/or make it his home. Or, if your far enough in the CW main quest that you're apart of Lyon's chapter of the Brotherhood you can use that rep to get into the Hidden Valley chapter with out the whole rigmarole of dealing with the ranger. Etc, etc, etc...
Also the DLCS have many ways of integrating. Like Christine / Veronica, so obvious, if you go though their dialogs and get their back stories, they are the two wayward lovers who got separated by Elijah, that there should be ways of telling one of the other so they can be rejoined. Or, at the last meeting with Joshua, and your doing a Legion run, to attack him and take his head back to Cesar for a massive reward. Etc, etc, etc. Again, just examples. :D
So what do you think? Be an interesting massive mod to do, yes? :D
